In this paper, we discuss challenges and provide solutions for capturing and maintaining accurate models of user profiles using semantic web technologies, by aggregating and sharing distributed fragments of user profile information spread over multiple services. Our framework for profile management allows for evolvable, extensible and expressive user profiles. We have implemented a prototype, targeting the retail domain, on the HP Labs Retail Store Assistant. Categories and Subject Descriptors H.3.4, H.3.5 [Information Storage and Retrieval]: Systems and Software ? User profiles and alert services; Online Information Services ? Data Sharing. General Terms Design, Management. Keywords User profiles, information management, semantic web, personalization